Males and females can differ in sex-linked traits. Genes on sex chromosomes are called sex-linked genes. Y chromosome genes in mammals are responsible for male characteristics.X chromosome genes in mammals affect many traits.

10.
Phenotype can depend on interactions of alleles.In incomplete dominance, neither allele is completely dominant nor completely recessive.Heterozygous phenotype is intermediate between the two homozygous phenotypesHomozygous parental phenotypes not seen in F1 offspring

Linkage maps estimate distances between genes. The closer together two genes are, the more likely they will be inherited together.Cross-over frequencies are related to distances between genes.Linkage maps show the relative locations of genes.

23.
Human genetics follows the patterns seen in other organisms. The basic principles of genetics are the same in all sexually reproducing organisms.Inheritance of many humantraits is complex.Single-gene traits areimportant in understandinghuman genetics.

24.
YXFemales can carry sex-linked genetic disorders. Males (XY) express all of their sex linked genes.Expression of the disorder depends on which parent carries the allele and the sex of the child.

25.
A pedigree is a chart for tracing genes in a family. Phenotypes are used to infer genotypes on a pedigree.Autosomal genes show different patterns on a pedigree than sex-linked genes.